Capillary electrophoretic techniques have assumed ever increasing importance as an analytical method for the detection and quantitation of biological molecules. The small diameter of the capillary affords a high degree of temperature control which permits the use of high voltages, separating molecules from complex biological mixtures from which the molecules are not otherwise separable or detectable. The small sample size is also an advantage in many cases, but a disadvantage in others. When therapeutic drugs are present in very low concentrations, for example, highly sensitive detection techniques such as laser-induced fluorescence are required.
Problems have also been encountered in the isolation and detection of certain biological compounds of neutral character which are highly soluble in water, since these qualities make it difficult to separate these compounds by traditional chromatographic techniques. Prevailing methods involve laborious extractions prior to the analysis, but even these are unsuitable for chromatographic techniques since they result in a relatively dilute solution of the analyte, requiring solvent removal before such techniques as high performance liquid chromatography can be employed.
These and other problems are addressed by the present invention.